Study On Water Consumption Characteristics And Water Productivity Of Typical Crops In The Loess Plateau

Water shortage is one of the main factors restricting agricultural production in northern China.The Loess Plateau is one of the most important water-deficient areas and semi-arid areas in China.As one of the most important dryland farming area in China,this area has long been affected by water shortages.In recent years,under the pressure of multiple factors such as population growth,water shortages and global warming,agricultural production has been greatly restricted,and the sustainable economic and social development of the region,especially poverty alleviation,has been enduring challenge.Therefore,it is very important to study the water use efficiency of food crops in the Loess Plateau.In the existing research,most of them focus on the study of water consumption and water production efficiency of single crops and large-scale macro-evaluation,while the systematic research on water efficiency of various crops on the regional scale is still scarce.How to scientifically understand the law of crop water consumption in the Loess Plateau and accurately understand the utilization efficiency of crop water resources is an important prerequisite for ensuring the sustainable development of agriculture in the region.This paper firstly summarizes the related researches on agricultural water use efficiency,crop water consumption and crop water productivity especially in the Loess Plateau.After systematically studying relevant research results and research progress,it is found that in relevant research at home and abroad,many important findings have been made in water cycle and utilization studies of certain crops,fixed-point farm experimental studies,and large-scale macro-evaluation studies,while there is insufficient attention to county-level mesoscale research.This study first selected the Anding District of Dingxi City,Gansu Province as experiment site.From 2015 to 2017,a three-year field experiment was conducted at the site.The research on the water consumption of different local crops and the performance evaluation study of FAO's water consumption model were carried out.By comparing the calculation results of the FAO model with the actual water consumption,it is found that the water consumption law between the four food crops?potato,corn,sorghum and buckwheat?measured by the experiment is significantly different.In terms of water consumption,The highest crop is sorghum with 329.98 mm,and the lowest water consumption is buckwheat with 186.68 mm.The RMSEs between the FAO calculated and the actual water consumption of the four crops are10.94 mm for potato,15.10 mm for corn,29.52 mm for sorghum and 15.22 mm for buckwheat.The average error is 17.70 mm,and the average error ratio is 7%.This indicates that the FAO's crop water consumption model has good applicability in the Loess Plateau.Based on the experimental research and the performance evaluation of the FAO model,this study used the FAO method to evaluate the crop water productivity?CWP?and calory crop water productivity?CCWP?of nine major food crops in four counties in northern Shaanxi.The results showed that:?1?The CWP of the region was 6.333 kg mm^-1 ha^-1,and the CCWP was 17683.81 kcal mm^-1 ha^-1,and the CWP of productive water?CWP-P?is 8.837 kg mm^-1 ha^-1,and the CCWP of productive water?CCWP-P?is 24769.07 kcal mm^-1 ha^-1.?2?Maize,sorghum and potato have the highest CWP,but potato has the lowest CCWP.?3?From the perspective of efficient use of water resources,there is still potential for adjustment and optimization of grain crop planting structures in northern Shaanxi.This research has good complementarity with existing research results.Between the study of water resources utilization law of large-scale agriculture and specific crop water use efficiency,a medium-scale research method of crop water consumption was explored,which has complementary value to existing research.This study combines meteorological data,hydrological data,social survey data and official statistical data to establish a link between the agricultural water cycle process and agricultural production activities,and provides an important research basis for further comprehensive understanding of the hydrological cycle process in the Loess Plateau.